In the normal practice of pulling cables or other flexible conduits, a considerable force must be initially applied to the cable to draw it from its reel or other holding mechanism. When the conduit is being drawn through a relatively spacious receptacle or even through an environment where it is unconfined, the pulling head utilized for applying the necessary pulling tension has virtually no limitations as to size. When, however, the conduit is to be pulled through aconfined conduit guide or other member, said member must be sufficiently large to permit the conduit as well as its pulling mechanism to pass therethrough.
Where the conduit guide is of relatively small diameter, the pulling head must likewise be sufficiently small to advance along the guide. Further it must advance without becoming entangled, jammed, or otherwise subjected to conditions that would cause the guide to be damaged.
In the instance of offshorre or subsea operations related to production of hydrocarbon liquids or gas, such flexible conduits are normally utilized in several capacities. Primarily they can be utilized for carrying a liquid or gas between an offshore location such as a drilling platform, to the shore. Alternately, the conduits may comprise conductors or electrical circuitry for communicating a remote well head to the control center located on the marine platform.
Normally in the instance of any offshore platform which is adapted to cover an expansive subterranean field or reservoir, the platform will be communicated to a number of remote well heads by way of conduits and electrical cables in the manner above stated. A primary feature which urges utilization of flexible type conduits is that they are more readily handled and can be installed without concern for their rigidity. Thus, they can be bent and adjusted to some extent to facilitate their being laid onto the ocean floor.
In the instance of many offshore or marine platforms, the structure is originally designed in contemplation of drilling a predetermined number of wells into a subterranean hydrocarbon containing reservoir. Thus, the platform is originally designed with a fixed number of conductors which are so positioned that each can readily accommodate a descending drill string. Therefore a well can be subsequently completed into a working unit through each conductor.
A platform of this nature is fixed and stable once it is piled into the ocean floor. It can however, be subsequently adapted to accommodate additional remotely located wells. This is achieved most readily by the provision of flexible conduits that extend from the platform, to the various well heads. The latter can then be operated from the platform, and further the product drawn from the well can be conducted to the platform processing equipment.
In such an instance, when it is desired to install additional conduits onto a platform for the above noted purpose, the conduits, wound on reels, are usually positioned on the platform. Thereafter, they are drawn by a pulling mechanism downwardly through one of the drilling conductors and out to the sea bed for connection to a conventional flowline.
The conduit installation operation can be achieved in a number of ways. However, in each instance it is necessary to firmly grasp the end of the flexible conduit, and exert enough axial pull that it can be unwound from its reel. It is thereafter pulled with a sufficient force that it will be positioned as desired on the ocean floor.
What is presently disclosed as a pulling head for removably engaging the end fitting of a flexible conduit or cable so that the latter can be forcefully drawn from a reel or the like. The head is adapted to engage the formed end of a cable fitting thereby establishing a sufficiently firm grip on the conduit that the needed pulling force can be appied thereto.
What is further provided is a pulling head of the type described which is of a diameter that it does not substantially exceed the diameter of the conduit being pulled. Thus, the flexible conduit can be drawn through a minimal sized guide or drilling conductor without concern that the pulling head will cause damage to the guide passage or to other members which it contacts during the pulling step.
It is therefore an object of the invention to provide a pulling head for a flexible conduit or similar cable type element, which pulling head is readily removable from the conduit end fitting. A further object is to provide a pulling head of the type contemplated which is capable of exerting an axial force to a conduit while drawing the latter through a limited size guide passage.
In achieving these objectives, the presently disclosed conduit pulling head is provided. The latter includes primarily a multi-segment ring or collar member that is adapted to be positioned on, and firmly grasp the end fitting of a conduit to be pulled. A nose piece detachably engages the ring and includes a wire line or similar member which can be of any desired length such that it can be connected to a pulling element such as a winch, a motor or the like.